drivers/media/dvb/pt1/pt1.c needs vmalloc.h
[linux-2.6.git] / fs / generic_acl.c
1 /*
2  * fs/generic_acl.c
3  *
4  * (C) 2005 Andreas Gruenbacher <agruen@suse.de>
5  *
6  * This file is released under the GPL.
7  */
8
9 #include <linux/sched.h>
10 #include <linux/fs.h>
11 #include <linux/generic_acl.h>
12
13 /**
14  * generic_acl_list  -  Generic xattr_handler->list() operation
15  * @ops:        Filesystem specific getacl and setacl callbacks
16  */
17 size_t
18 generic_acl_list(struct inode *inode, struct generic_acl_operations *ops,
19                  int type, char *list, size_t list_size)
20 {
21         struct posix_acl *acl;
22         const char *name;
23         size_t size;
24
25         acl = ops->getacl(inode, type);
26         if (!acl)
27                 return 0;
28         posix_acl_release(acl);
29
30         switch(type) {
31                 case ACL_TYPE_ACCESS:
32                         name = POSIX_ACL_XATTR_ACCESS;
33                         break;
34
35                 case ACL_TYPE_DEFAULT:
36                         name = POSIX_ACL_XATTR_DEFAULT;
37                         break;
38
39                 default:
40                         return 0;
41         }
42         size = strlen(name) + 1;
43         if (list && size <= list_size)
44                 memcpy(list, name, size);
45         return size;
46 }
47
48 /**
49  * generic_acl_get  -  Generic xattr_handler->get() operation
50  * @ops:        Filesystem specific getacl and setacl callbacks
51  */
52 int
53 generic_acl_get(struct inode *inode, struct generic_acl_operations *ops,
54                 int type, void *buffer, size_t size)
55 {
56         struct posix_acl *acl;
57         int error;
58
59         acl = ops->getacl(inode, type);
60         if (!acl)
61                 return -ENODATA;
62         error = posix_acl_to_xattr(acl, buffer, size);
63         posix_acl_release(acl);
64
65         return error;
66 }
67
68 /**
69  * generic_acl_set  -  Generic xattr_handler->set() operation
70  * @ops:        Filesystem specific getacl and setacl callbacks
71  */
72 int
73 generic_acl_set(struct inode *inode, struct generic_acl_operations *ops,
74                 int type, const void *value, size_t size)
75 {
76         struct posix_acl *acl = NULL;
77         int error;
78
79         if (S_ISLNK(inode->i_mode))
80                 return -EOPNOTSUPP;
81         if (!is_owner_or_cap(inode))
82                 return -EPERM;
83         if (value) {
84                 acl = posix_acl_from_xattr(value, size);
85                 if (IS_ERR(acl))
86                         return PTR_ERR(acl);
87         }
88         if (acl) {
89                 mode_t mode;
90
91                 error = posix_acl_valid(acl);
92                 if (error)
93                         goto failed;
94                 switch(type) {
95                         case ACL_TYPE_ACCESS:
96                                 mode = inode->i_mode;
97                                 error = posix_acl_equiv_mode(acl, &mode);
98                                 if (error < 0)
99                                         goto failed;
100                                 inode->i_mode = mode;
101                                 if (error == 0) {
102                                         posix_acl_release(acl);
103                                         acl = NULL;
104                                 }
105                                 break;
106
107                         case ACL_TYPE_DEFAULT:
108                                 if (!S_ISDIR(inode->i_mode)) {
109                                         error = -EINVAL;
110                                         goto failed;
111                                 }
112                                 break;
113                 }
114         }
115         ops->setacl(inode, type, acl);
116         error = 0;
117 failed:
118         posix_acl_release(acl);
119         return error;
120 }
121
122 /**
123  * generic_acl_init  -  Take care of acl inheritance at @inode create time
124  * @ops:        Filesystem specific getacl and setacl callbacks
125  *
126  * Files created inside a directory with a default ACL inherit the
127  * directory's default ACL.
128  */
129 int
130 generic_acl_init(struct inode *inode, struct inode *dir,
131                  struct generic_acl_operations *ops)
132 {
133         struct posix_acl *acl = NULL;
134         mode_t mode = inode->i_mode;
135         int error;
136
137         inode->i_mode = mode & ~current_umask();
138         if (!S_ISLNK(inode->i_mode))
139                 acl = ops->getacl(dir, ACL_TYPE_DEFAULT);
140         if (acl) {
141                 struct posix_acl *clone;
142
143                 if (S_ISDIR(inode->i_mode)) {
144                         clone = posix_acl_clone(acl, GFP_KERNEL);
145                         error = -ENOMEM;
146                         if (!clone)
147                                 goto cleanup;
148                         ops->setacl(inode, ACL_TYPE_DEFAULT, clone);
149                         posix_acl_release(clone);
150                 }
151                 clone = posix_acl_clone(acl, GFP_KERNEL);
152                 error = -ENOMEM;
153                 if (!clone)
154                         goto cleanup;
155                 error = posix_acl_create_masq(clone, &mode);
156                 if (error >= 0) {
157                         inode->i_mode = mode;
158                         if (error > 0)
159                                 ops->setacl(inode, ACL_TYPE_ACCESS, clone);
160                 }
161                 posix_acl_release(clone);
162         }
163         error = 0;
164
165 cleanup:
166         posix_acl_release(acl);
167         return error;
168 }
169
170 /**
171  * generic_acl_chmod  -  change the access acl of @inode upon chmod()
172  * @ops:        FIlesystem specific getacl and setacl callbacks
173  *
174  * A chmod also changes the permissions of the owner, group/mask, and
175  * other ACL entries.
176  */
177 int
178 generic_acl_chmod(struct inode *inode, struct generic_acl_operations *ops)
179 {
180         struct posix_acl *acl, *clone;
181         int error = 0;
182
183         if (S_ISLNK(inode->i_mode))
184                 return -EOPNOTSUPP;
185         acl = ops->getacl(inode, ACL_TYPE_ACCESS);
186         if (acl) {
187                 clone = posix_acl_clone(acl, GFP_KERNEL);
188                 posix_acl_release(acl);
189                 if (!clone)
190                         return -ENOMEM;
191                 error = posix_acl_chmod_masq(clone, inode->i_mode);
192                 if (!error)
193                         ops->setacl(inode, ACL_TYPE_ACCESS, clone);
194                 posix_acl_release(clone);
195         }
196         return error;
197 }